During 2005, I purchased a few Range Rover type 4CU ECU's from Ebay to facilitate an experiment fitting them to my Twin Plenum Rover SD1 Vitesse and measuring the performance results.

Several tests were performed on each ECU over an identical test run and measurements taken via the Rover SD1 trip computer. The conditions were similar for each test and the results can be viewed in tabular form with my comments as appropriate for each ECU.

My conclusion was that whilst the Range Rover ECU's did mostly work in the Rover SD1Efi system they were not totally satisfactory.

The experiment was not fully completed as it remains to be seen if the relatively small idle speed problems can be eliminated for the respective ECU's by adjusting the system.